Potential benefit will be a durable resolution or improvement of the leg ulcer. Possible side effects include hypotension and methemoglobinemia, secondary to sodium nitrite absorption for the ulcerated skin. Safety measures will be used and pharmacokinetics analysis of sodium nitrite absorption in this setting will be obtained. As a secondary endpoint, we will study the biology of leg ulcer formation in patients with hemolytic disorders, its pathological appearance on a skin biopsy, and the role of microvascular changes in its formation and (possibly) resolution. Sophisticated and novel studies of blood flow and temperature changes during sodium nitrite application, as well as macrovascular appearance on MRI will allow for a better understanding of ulcer formation. This may lead to novel approaches to the therapy of ulcer in hemolytic and non-hemolytic disorders, such as diabetes and decubitus ulceration.